mail.adampolnet.com has no CNAME records.
Question and response
Question
dig mail.adampolnet.com. NS
Answer
The response has no answer records.
Authority
adampolnet.com. 1800 SOA dns.adampolnet.com. host.adampolnet.com. 2026011201 3600 3600 3600 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0